In the wake of criticism over a two-game suspension for Baltimore Ravens running back Ray Rice , the NFL has established a six-game unpaid ban for personnel who violate the league 's policy on domestic violence , Commissioner Roger Goodell said Thursday .

A second incident would be punished by a lifetime ban from the league , Goodell said in a letter and memo to the owners of the league 's 32 teams .

Without referring to Rice by name , he acknowledged in his letter that he made the wrong decision in that case .

`` I did n't get it right . Simply put , we have to do better . And we will , '' he wrote .

The policy , which is effective immediately , also applies to other types of violence .

`` Violations of the Personal Conduct Policy regarding assault , battery , domestic violence or sexual assault that involve physical force will be subject to a suspension without pay of six games for a first offense , with consideration given to mitigating factors , as well as a longer suspension when circumstances warrant . ''

Goodell said the circumstances that would warrant a longer suspension include incidents that predate a person 's time with an NFL team or acts that involve choking , repeated blows or a weapon . They also include violence against a pregnant woman or in view of child .

Lifetime bans may be appealed after a year .

The players union issued a response .

`` We were informed today of the NFL 's decision to increase penalties on domestic violence offenders under the Personal Conduct Policy for all NFL employees . As we do in all disciplinary matters , if we believe that players ' due process rights are infringed upon during the course of discipline , we will assert and defend our members ' rights , '' the NFL Players Association said in its statement .

Read the letter and memo

Rice was suspended for two games after video showed him dragging his unconscious fiancee -- whom he later married -- from an elevator .

Rice resolved the charges stemming from the incident with his now-wife , Janay , and entered a pretrial intervention program in May , the NFL said . Under the program , he wo n't be prosecuted , and the charges will be expunged after a year , the league said .

The punishments , both from the NFL and from the criminal justice system , were widely decried as too light , and the issue quickly spiraled into debates over domestic violence and victim-blaming .

Opinion : NFL , apologize to women for Ray Rice

Goodell 's letter tells teams to distribute a memo about the new policy to each player and all members of the organizations .

The NFL 's Personal Conduct Policy states that employees are `` held to a higher standard '' of conduct .

`` Persons who fail to live up to this standard of conduct are guilty of conduct detrimental and subject to discipline , even where the conduct itself does not result in conviction of a crime , '' the policy states .

The NFL regular season is 16 games .

Ravens ' Ray Rice : ` My actions were inexcusable '

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Players union says it will continue to defend players rights

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The new policy takes effect immediately , NFL Commissioner Roger Goodell says

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The commissioner admitted he should have punished Ray Rice more severely

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Rice got two-game suspension after video showed him dragging his now-wife